In recent years, a high definition multimedia interface (HDMI) has been widely used as a communication interface that transmits at a high speed a digital video signal, that is, an uncompressed (baseband) video signal (image data), and a digital audio signal (audio data) accompanying the video signal, for example, from a digital versatile disc (DVD) recorder, a set-top box, or other audio visual (AV) sources to a television receiver, a projector, or other displays. For example, Non-Patent Document 1 describes a specific HDMI standard.
For example, an AV system or the like may have a disc player serving as a source device and a television receiver serving as a sink device coupled to each other by means of the HDMI. The luminance of image data recorded in the disc player is adjusted on the assumption that the image data are displayed on a display device for which a maximum luminance of 100 cd/m2 is specified.
However, owing to advances in technology, a display device having a maximum luminance of about 1000 cd/m2 exceeding the conventional maximum luminance of 100 cd/m2 has been put into practical use, and the high-luminance output capability of the display device has not been sufficiently utilized.
In this regard, a high dynamic range (HDR) process has been proposed and put into practical use for still image capturing and a post process. In the HDR process, a luminance dynamic range process is performed, that is, a maximum luminance process for image data is performed so that the maximum luminance exceeds 100 cd/m2. For example, Patent Document 1 has proposed a system of recording HDR image data and a process therefor.